Hung windows are well known. Single hung windows have a window frame that comprises a fixed glass pane and a sash having a glass pane, the sash being vertically slidable within the window frame. Double hung windows have two sashes, each having a glass plane, which are vertically slidable within the window frame.
Also well known are pivotable hung windows. For these, fixtures at the bottom of a sash pivotally engage cooperating fixtures disposed in opposite vertical channels of the window frame. A releasable latch mechanism is disposed at the top part of the sash and allows a user to pivot the sash to the inside of the building in which the window is installed. These pivotable hung windows allow for easy cleaning of the exterior of the window pane from the inside of the building.
Additionally, hung windows usually include a lock mechanism for locking together the top and bottom windows in a closed position. In addition to providing security to the building, the lock mechanism provides additional structural strength to the window assembly. This added strength is desirable particularly in stormy weather where strong winds prevail. However, the additional structural strength is only present when the lock mechanism is engaged.
Hung window sashes made of materials such as PVC tend to bend under strong wind pressure, sometimes causing them to dislodge from the window frame. Additionally, the latch mechanisms of pivotable window sashes in general can fail in such weather conditions. Consequently, window sashes can abruptly open and cause damage to the window unit and to the building.
To address the problem of abruptly opening hung windows, several window brackets, or snubbers, for hung windows have been developed. One such type of bracket is disclosed in U.S. Pat. No. 6,363,659 to Wang. The bracket includes an L-shaped part (20) for securing to a vertical side of the window frame and a Z-shaped part (10) for securing to a corresponding vertical member of the window sash. The bracket L-shaped and Z-shaped parts are mounted hidden from sight on respective planes parallel to each other and perpendicular to the glass pane plane. The bracket parts are of cooperating shape such that when mounted and with the window closed, the brackets parts overlap and interlock to prevent pivoting of the window sash. This type of bracket can be adequate for windows framed in aluminum or wood where bending under pressure is not considerable, but inadequate for PVC window units. The bending of PVC in strong winds is such that the interlocking mechanism of the L-shaped bracket and the Z-shaped bracket can fail and the hung window pop open.
Additionally, the Wang bracket parts are not easy to install. Installation of the bracket parts requires that the window sash be pivoted in the open position. Further, the Z-shaped part requires that a worker have access to each side of sash. This can be impossible in cases where the window unit is installed close to an interior perpendicular wall of the building. In such cases, the window sash has to be removed from the window frame to install the part. Furthermore, the Z-shaped part includes parallel, spaced-apart, segments that are for abutting to parts of the window sash. These bracket features have to match the dimensions and the features of the window sash. As such, a given Wang bracket is not adapted to fit to window sashes of different dimensions.
Another type of bracket for providing impact resistant window units is disclosed in U.S. Patent Application Publication No. 2005/0155301A1 to Hapka et al., hereinafter referred to as Hapka. The Hapka bracket is fitted in the frame of the window unit, on the inside of the building. The bracket includes a movable bracket portion which can be in an extended or retracted position, overlapping the window sash in the extended position. When in the extended position, the movable bracket portion abuts the window sash thereby providing additional structural force to the window sash in strong wind conditions. When in the retracted position, the movable bracket portion allows a pivotable window sash to pivot for cleaning. However, the Hapka bracket requires significant work for retrofitting in existing windows.
Consequently, there is a need in the pivotable hung window art for an affordable bracket, or snubber, system that can be easily retrofitted to existing windows and that provides additional structural strength to window unit to sustain strong winds.